prvi kongres hrvatskih znanstvenika iz domovine i inozemstva - HATZ

PRVI KONGRES HRVATSKIH ZNANSTVENIKA IZ DOMOVINE I INOZEMSTVAZagreb - Vukovar, 15. - 19. studenog 2004.P - 2DOUBLE BREMSSTRAHLUNG IN PROTON-PROTON SCATTERINGAT 190 MeVJ.C.S. Bacelar a ; R. Castelijns a ; R. Čaplar b ; K. Ermisch a ; I. Gašparić b ; M.N. Harakeh a ;N. Kalantar-Nayestanaki a ; M. Kiš a ; H. Loehner a ; M. Mahjour-Shafiei aa Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen, The Netherlandsb Ruñer Bošković Institute, Zagreb, CroatiaMany properties of the strong force can be exhaustively examined in proton-protoncollision experiments. Since the elastic proton-proton scattering is well described byexisting models, there is a challenge to investigate higher-order effects. These effects areemphasized in processes such as real [1], virtual [2] and double bremsstrahlung. All ofthem offer a detailed insight into the proton-proton interaction and each of themdistinguishes itself by some special features. In particular, double bremsstrahlung, apartfrom being an extension of real bremsstrahlung, covers the emission of a virtual 7r°meson.In our experiment with a 190 MeV proton beam delivered by the AGOR cyclotron at theKVI, two detectors were used: The Small-Angle Large-Acceptance Detector (SALAD) [3]for protons emitted at forward polar angles and Plastic Ball [4] for gammas and leptonsemitted at medium and backward polar angles. These detectors and additionalelectronics allow a fast rejection of a huge amount of background elastic scatteredprotons during the experiment.A kinematical overdetermination of the events permits a good selection of proper eventsin the offline analysis. The results obtained so far show that the number of recordeddouble gamma events is of the order of a few tens of thousends. A production ofsimulated events based on the Two-Soft-Photon Model [5] is currently in progress.Presented on:18 th European Conference on Few-Body Problems,Bled, Slovenia, 7-14 September, 2002Principal Investigator : Dr.sc. Zoran BasrakProject No. 00980104